#include <stdio.h>

FILE *openFile(const char *filename);
void catFile(FILE *file);

int main(int argc, char *argv[]) {

  if (argc != 2) {
    printf("error: missing file\nusage: cat <filename>\n");
    return -1;
  }

  FILE *file = openFile(argv[1]);
  if (!file) {
    printf("error: file (%s) not found\n", argv[1]);
    return -2;
  }

  catFile(file);

  fclose(file);

  return 0;
}

FILE *openFile(const char *filename) {
  FILE *file;

  file = fopen(filename, "r");

  return file;
}

void catFile(FILE *file) {
  char buf[512];
  while (fgets(buf, 512, file)) {
    printf("%s", buf);
  }
}